Question

I am designing a custom blog in PHP. On my panel I have the heading “Categories” and I list the categories and how many posts are in each category. There are 2 related tables, posts, and post_categories.

POSTS – post_id, post_title, post,
category_id

POST_CATEGORIES – category_id,
category_name, post_id

I’d prefer not to add a category of uncategorised as this will cause me issues with future features I plan to design. My SQL for this is:

SELECT *, COUNT(*) AS category_post_count
FROM post_categories, posts
WHERE posts.category_id = post_categories.category_id
GROUP BY category_name

Now if a post is not set with a category_id, it is given a category_id of 0 and will not related to anything in post_categories. How can I group these in my SQL statement AS uncastegorised?

Thanks.

Answer 1

You can do a left join to also include any posts that don’t have a category.

SELECT *, COUNT(*) as category_post_count
FROM post_categories LEFT JOIN posts
  ON posts.category_id = post_categories.category_id
GROUP BY category_name;